maint: maintainer-release-check.

[bison.git] / configure.ac

diff --git a/configure.ac b/configure.ac
index 688e18efe74bb137d714af6fc24ea59f616e57ae..3c3fa421474692370f5146c2a57861e60b316d39 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -114,6 +114,7 @@ AC_SUBST([YACC_LIBRARY])
 
 # Checks for programs.
 AC_PROG_LEX
+$LEX_IS_FLEX || AC_MSG_ERROR([Flex is required])
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4